Jackass stars Johnny Knoxville and Bam Margera paid their respects to co-star Ryan Dunn at a private memorial service in West Chester, Pennsylvania.

Dunn and his passenger, Zachary Hartwell, were killed earlier this week after the 34-year-old star lost control of his Porsche while going at least 130 mph ... eventually crashing into a tree. The sports car burst into flames upon impact. Toxicology results show that Dunn was drunk at the time of the crash.

There will be a public funeral service that will take place later this week. Picketers from the Westboro Baptist Church are expected. The funeral director, Joe DellaVecchia, says police will be present to maintain control. He adds:

"We can't stop someone from coming to a public funeral, but this is private, and the police have everything under control"

Bam Margera recently broke down at the site of the crash. Watch the video ... after the jump.